<p>Fracture closure is a very important issue in production. To investigate the fracture closure mechanism for the reservoir treated by acidization, both experiment and numerical simulation are conducted. It is found that the acidization can sharpen the asperity by resolving the lateral side since the acidic fluid cannot penetrate into the contact interface. The sharpened asperity induces a strong stress concentration around the contact area, which initiates the radial fractures in the support rock matrix, resulting in the fragmentation of support matrix. Consequently, the fracture closure occurs. This mechanism of fracture closure is further validated through the numerical simulation. The fracture face support failure due to the acidization-induced geometry evolution is an important mechanism of fracture closure. It is inadequate to attribute the acidized fracture closure solely to the rock weakening effect. The research result reveals different underlying mechanism of the fracture closure treated by acidization.</p>